Reproduction AHL

Topic 11.4

11.4.1 & 11.4.3: The testis and the effects of LH, testosterone and FSH

Annotated light micrograph of testis tissue to show the location and function of interstitial cells (Leydig cells), germinal epithelium cells, developing spermatozoa and Sertoli cells.

Structure of the testis

11.4.2: Spermatogenesis

Spermatogenesis occurs with the testis and includes mitosis, cell growth, two divisions of meiosis and cell differentiation as outlined below.

spermatogenesis link spermatogenesis animation
The process of spermatogenesis

11.4.4: The ovary

Annotated diagram of the ovary to show the location and function of germinal epithelium, primary follicles, mature follicle and secondary oocyte.

Structure of the ovary

11.4.5: Oogenesis

Oogenesis occurs within the ovary and includes mitosis, cell growth, two divisions of meiosis, the unequal distribution cytoplasm and the degeneration of polar bodies as outlined below.

oogenesis link oogenesis animation
The process of oogenesis

11.4.6: Sperm and egg structures

Shown below are the different structures of a mature sperm cell and an mature egg cell.

Structure of sperm and egg

11.4.7: Role of the epididymis, seminal vesicle and prostate gland in the production of semen.

Male Reproductive System

11.4.8: Comparing spermogenesis and oogenesis

compare sperm egg link compare sperm egg animation
Comparing spermogenesis and oogenesis

11.4.10: The process of fertilization

Acrosomal and Cortical Reactions

The process of fertilization includes acrosomal reaction, penetration of the egg membrane by the sperm, the cortical reaction and diffusion of the sperm nucleus with the egg nucleus. After ejaculation the sperm moves through the uterus and enters the fallopian tube as it swims towards the egg attracted by chemicals (chemotaxis). Once sperm reach the egg it must swim through the follicle cells that surround the egg and move through the zona pellucida. The necessary reactions are shown in the figure below.

Placing your mouse pointer on the figure below will show the explanations for the acrosomal and cortical reactions.

The acrosomal and cortical reactions

Fertilization produces a diploid zygote

Fertilization produces a diploid zygote

11.3.10 & 11.3.11: Implantation of the blastocyst

After fertilization the diploid zygote moves down the fallopian tube and undergoes several mitotic divisions resulting in a hollow ball of cells called the blastocyst (shown below). The blastocyst implants in the uterine wall and begins to secrete a hormone called human chorionic gonadotropin space (HCG). The HCG maintains the production of estrogen and progesterone by the corpus luteum of the ovary during the first few months of pregnancy. If these hormones are not present, menstruation will occur, and the embryo will be spontaneously aborted.

Implantation of the blastocyst

11.3.12 - 11.3.14: The role of the placenta?

The figure below shows the structures of the placenta. The functions of the placenta include the secretion of the hormones estrogen and progesterone which help maintain the pregnancy and are explained by placing your mouse pointer on the figure. Note that the fetus supported and protected by the amniotic sac in the amniotic fluid and materials are exchanged between the maternal and fetal blood in the placenta.

Place your mouse on the figure to see the role of the placenta during pregnancy.

Functions of the placenta

11.3.15: The process of birth

The process of birth
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